Leakage Inspection for Crown Caps





Among the inspection of underfilled

bottles or bottles without seal or label,

the inspection of leaking bottles is an

essential requirement to quality assurance

in the beverage industry. Leakages

influence the quality and durability

of products directly and thus are

not acceptable for consumers or bottlers.

Therefore leakage inspectors are

standard products of quality management

in the beverage industry.

The acoustic technology of BBULL

MAS/P is for indirect pressure measurement

in CO2 containing beverages.

The MAS technology can be applied

for glass bottles with metal cap, that

do not have any measurable deflection,

e.g. beer bottles with crown cork.

The acoustic sensor MAS works by applying

an electromagnetic impulse to

the top of each container. The “pulse”

is produced by a strong electromagnetic

pulse, which excites the container

lid. The lid vibrates at an individual

resonant frequency “tone”, based on

internal pressure. The resulting “acoustic”

signal is received by a microphone,

digitally sampled and stored in

memory for processing. The pc-based

processing software produces a realtime

signal spectrum and calculates

the resulting frequency of the “signal”

for every lid. Thereby the internal

pressure is directly proportional to the

vibration frequency of the inspected


Additionally the lid deflection is inspected

by „analogue proximity technology“.

An electromagnetic proximity

sensor produces a permanent

magnetic field for monitoring the distance

between sensor and metal cap

and produces a distance-depending

proportional analogue voltage. The

permanent proximity signal is digitally

sampled for producing a performance-related

value of the cap profile.

The profile value as well as the frequency

value of the closure is compared

with the user set limits of container

format in which containers with

a frequency response outside these

limits are rejected.

BBULL MAS inspection head


recognition of too little pressure /


recognition of too much pressure

recognition of cap leakage

recognition of hair cracks

recognition of missing compound

recognition of broken glass in the

area of the neck

recognition of cocked caps

BBULL MAS sensor bridge



For getting high measuring accuracy

we recommend the maximum possible

distance from the closer to BBULL

MAS/P So there is enough time to set

up a pressure inside the container

which is reduced in case of leakages.

Best results can be achieved in combination

with a pasteurizer, after labeller.



The inspection principle allows the

detection of leakers only when the

product specific pressure has been

reached. This pressure is basically depending

on the CO 2 -level or temperature

of the product. A reliable measurement

is only possible when the pressure

inside the faulty bottles is decreased

significantly to differ faulty bottles from

good bottles.

To reach constant measurements we

recommend maximum possible distance

from the closer to the BBULL

MAS/P Leaking bottles must reduce the

internal pressure to differ constantly

from good bottles .

Thus a statement of inspection reliability

is always depending of the installation

place and is always related to the difference

to the normal pressure of good




The processing software of BBULL

MAS/P is installed on a pc-based Inspection


BBULL offers the basic configuration

with a BBULL 400 control unit, with 6,4”

touch display with alphanumeric user


In combination with monitoring systems

BBULL 4000 with 15“ touch and

graphical user interface BBULL offers

additional inspections like e.g. camera-based

label or cap inspections.



fill level Inspection

label inspection

cap inspection

rejection system for faulty bottles


Max. line speed in bottles per hour: 75.000

Power supply in V: 24 (18 - 30)

Power consumption in VA: < 10

Surrounding temperature in °C: 5 – 42

Network interface: Ethernet

Sensor system: 1. Analogue proximity sensor

2. Magnet acoustic

Dimensions inspection bridge (WxHxD) in mm: 450x260x170

Weight inspection bridge in Kg: 12

Enclosure: IP33

STRATEC CONTROL-SYSTEMS GmbH • Ankerstrasse 73 • 75203 Königsbach-Stein

Telefon (+49) 72 32- 40 06- 0 • Telefax (+49) 72 32- 40 06- 25

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